this.onmessage = function(e){
	// console.log("onmessage",e);
	console.log("开始计算！")
	let time = Date.now();
	let num = 0;
	for(let i=0;i<e.data;i++){
		num+=Math.random();
	}
	console.log("计算结束,结果："+num,"花费的时间："+(Date.now()-time));
	this.close();
}